This invention relates to apparatus for compacting metal shavings, chips and the like into easily transportable pellets. More particularly, the invention compacts metal shavings to remove cutting fluids, such as oil from the shavings, and to compact the shavings into pellets so that the cutting fluid and the metal shavings may be separately recycled.
In metal working shops, metal shavings, chips or the like result from hot-working the metal during fabrication of parts. Examples of hot-working metal include cutting and grinding and other processes where the metal is cut to shape the metal. It has been the practice in most shops to collect the shavings, chips and the like, and send them to a foundry for recycling. The cutting, grinding or other hot-working process usually requires the use of cutting fluid, such as cutting oils, to disperse heat from the part being produced during the hot-working process. Excess cutting fluid is collected, cleaned and recycled, often directly back to the machine tool performing the hot-working process. Excess oil on the parts produced may be collected by drip-drying or other processes to again return the cutting fluid to be cleaned and recycled. However, it has not been practical to collect cutting fluid from the metal shavings. Instead, most machine shops have simply collected the metal shavings for pickup by the foundry where the shavings are subjected to high temperature to burn off the oil and reduce the shavings to a usable metal.
Currently, foundries accept oil-laden waste metal for recycling. However, environmental concerns require firing oil-soaked metal shavings in specially constructed furnaces which prevent hydrocarbon discharge. Hence, the cost of recycling such oil-laden shavings is high. Moreover, interstices formed by the shavings decreases the over-all density of the metal, thereby increasing transportation costs.
While compactors exist for compacting organic waste for ease of transportation and other uses (including manufacturing organic pellets for fuel), there is no effective, economic compactor for compacting metal shavings, chips and the like to extrude cutting oil therefrom and to compact the metal into pellets suitable for transportation. More particularly, while organic compactors operate at pressures of about 1,000 to 1,500 pounds per square inch (psi), and some as high as 6,000 psi, at least 20,000 psi pressure is necessary to compact metal shavings, chips and the like. Moreover, compactors of organic material usually include drain ports from the compaction chamber to permit fluids to be extruded for collection. While the drain ports operate quite satisfactory for organic wastes at the low pressure of compaction (1,000 to 1,500 psi), drain ports would not be practical at the high pressure required for metal shavings compaction, because the high pressure would force metal into the drain thereby impairing the operation of the device.
The present invention is directed to a compactor for compacting metal shavings to a condensed pellet, absent of interstices and of significant amounts of cutting fluid. Using the present invention, cutting fluid is forced from the interstices of the metal shavings under pressure and collected for cleaning and recycling. The shavings are compacted into a compressed pellet suitable for easy handling and transportation.
As an example of the savings to the machine working shop employing the present invention, foundries currently pay about $20.00 per ton for oil-laden metal shavings for processing by the foundry to reclaim the metal. In contrast, foundries currently pay about $60.00 per ton for the pellets formed using the present invention, primarily because the pellets to not require processing to remove the oil and are easier to handle. Moreover, the present invention permits the metal working shop to recover additional cutting fluids for use within the shop.